Depth finder shuts off

I installed a new depth finder on my boat as an upgrade to one it had when I bought it. I wired into the existing switch on my console where the previous df was installed. I hop in the boat, fire up my motor, fire up the df and head down the lake, no problem. Gety to my spot, shut down the main motor, fish for awhile, no problem. When I fire up the big motor to head to another spot, my df turns off. It will turn back on, but I'm a little irritated and concerned that I'm getting a power interruption or surge to the df. Suggestions? I wired it in with the standard in line fuse, but nothing else.

The dash switch is tied into the ignition. Wire your switch direct, bypassing the ignition.

I had the same thing happen....check your battery. If your battery isn't holding a good charge and you're drawing it down with accessories while fishing, when you start your big motor you are dropping the voltage below the threshold of the finder and it will shut down. I replaced my battery and problem solved. I would have your battery load tested, even if it's fairly new.

MackayGuy said:

I had the same thing happen....check your battery. If your battery isn't holding a good charge and you're drawing it down with accessories while fishing, when you start your big motor you are dropping the voltage below the threshold of the finder and it will shut down. I replaced my battery and problem solved. I would have your battery load tested, even if it's fairly new.

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mac guy is right I've had the same type of issues when my batteries get low.

I had the same issue due to the fact it is a long ways from the battery to the fish finder. I ran a separate 12 gauge fused wires from the battery to the FF and it no longer does it

Mine is wired on the hot side and not the ignition side. Never any issue with shutting off when starting.

It has to do with the power drain of your engines starter motor. Your fish finder shuts off at about 10.5 volts and when the engine is starting it pulls the voltage down; put a volt meter on it and check the reading while the engine is being cranked. If you are using a deep cycle battery that may contribute because it is made for a long slow drain not a high amp drain of a starter motor. Best way to cure it is to have two batteries. One for the engine and one for accessories.